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Interquartile Range Conceptual Explanation Interquartile Range
27

Inter quartile range

Jul 15, 2015

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Page 1: Inter quartile range

Interquartile Range

Conceptual Explanation

Interquartile Range

Page 2: Inter quartile range

Interquartile Range

The interquartile range represents the distance between the 25th percentile and 75th percentile.

Interquartile Range

Page 3: Inter quartile range

Interquartile Range

The interquartile range represents the distance between the 25th percentile and 75th percentile.

1 2 3 4 5 6 7 8 9

1

2

3

4

5

Interquartile Range

Page 4: Inter quartile range

Interquartile Range

The interquartile range represents the distance between the 25th percentile and 75th percentile.

1 2 3 4 5 6 7 8 9

1

2

3

4

5

25th

percentile

Interquartile Range

Page 5: Inter quartile range

Interquartile Range

The interquartile range represents the distance between the 25th percentile and 75th percentile.

50th

percentile

1 2 3 4 5 6 7 8 9

1

2

3

4

5

25th

percentile

Interquartile Range

Page 6: Inter quartile range

Interquartile Range

The interquartile range represents the distance between the 25th percentile and 75th percentile.

50th

percentile

1 2 3 4 5 6 7 8 9

1

2

3

4

5

25th

percentile

This is called the MEDIAN

Interquartile Range

Page 7: Inter quartile range

Interquartile Range

The interquartile range represents the distance between the 25th percentile and 75th percentile.

50th

percentile

1 2 3 4 5 6 7 8 9

1

2

3

4

5

25th

percentile75th

percentile

Interquartile Range

Page 8: Inter quartile range

Interquartile Range

The interquartile range represents the distance between the 25th percentile and 75th percentile.

50th

percentile

1 2 3 4 5 6 7 8 9

1

2

3

4

5

25th

percentile75th

percentile

This means that 25% of the scores fall below this point.

Interquartile Range

Page 9: Inter quartile range

Interquartile Range

The interquartile range represents the distance between the 25th percentile and 75th percentile.

50th

percentile

1 2 3 4 5 6 7 8 9

1

2

3

4

5

25th

percentile75th

percentile

This means that 25% of the scores fall below this point.

This means that 75% of the scores fall below this point.

Interquartile Range

Page 10: Inter quartile range

Interquartile Range

The interquartile range represents the distance between the 25th percentile and 75th percentile.

1 2 3 4 5 6 7 8 9

1

2

3

4

5

25th

percentile75th

percentile

Interquartile Range

Page 11: Inter quartile range

Interquartile Range

The interquartile range represents the distance between the 25th percentile and 75th percentile.

1 2 3 4 5 6 7 8 9

1

2

3

4

5

25th

percentile75th

percentile

Interquartile Range

Page 12: Inter quartile range

Interquartile Range

The interquartile range represents the distance between the 25th percentile and 75th percentile.

1 2 3 4 5 6 7 8 9

1

2

3

4

5

25th

percentile75th

percentile

50% of the scores fall between these two

points

Interquartile Range

Page 13: Inter quartile range

Interquartile Range

The interquartile range represents the distance between the 25th percentile and 75th percentile.

1 2 3 4 5 6 7 8 9

1

2

3

4

5

25th

percentile75th

percentile

50% of the scores fall between these two

points

This is the Interquartile Range!

Interquartile Range

Page 14: Inter quartile range

Purposes of the Interquartile Range (IQR)

Interquartile Range

Page 15: Inter quartile range

Purposes of the Interquartile Range (IQR)

The Interquartile Range (IQR) is a helpful measure of spread for two scenarios.

Interquartile Range

Page 16: Inter quartile range

Purposes of the Interquartile Range (IQR)

The Interquartile Range (IQR) is a helpful measure of spread for two scenarios.

1. Rank ordered Data

Interquartile Range

Page 17: Inter quartile range

Purposes of the Interquartile Range (IQR)

The Interquartile Range (IQR) is a helpful measure of spread for two scenarios.

1. Rank ordered Data

9t 8t 7t

7t

5t

6t

6t

5t 4t

6t

5t

5t

3d 2d 1st

1 2 3 4 5 6 7 8 9

1

2

3

4

5

3d4t

4t

Interquartile Range

Page 18: Inter quartile range

Purposes of the Interquartile Range (IQR)

The Interquartile Range (IQR) is a helpful measure of spread for two scenarios.

1. Rank ordered Data

9t 8t 7t

7t

5t

6t

6t

5t 4t

6t

5t

5t

3d 2d 1st

1 2 3 4 5 6 7 8 9

1

2

3

4

5

3d4t

4t First

Interquartile Range

Page 19: Inter quartile range

Purposes of the Interquartile Range (IQR)

The Interquartile Range (IQR) is a helpful measure of spread for two scenarios.

1. Rank ordered Data

9t 8t 7t

7t

5t

6t

6t

5t 4t

6t

5t

5t

3d 2d 1st

1 2 3 4 5 6 7 8 9

1

2

3

4

5

3d4t

4t FirstLast

Interquartile Range

Page 20: Inter quartile range

Purposes of the Interquartile Range (IQR)

The Interquartile Range (IQR) is a helpful measure of spread for two scenarios.

1. Rank ordered Data

2. Highly Skewed Data

Interquartile Range

Page 21: Inter quartile range

Purposes of the Interquartile Range (IQR)

The Interquartile Range (IQR) is a helpful measure of spread for two scenarios.

1. Rank ordered Data

2. Highly Skewed Data

1 2 3

3

5

4

4

5 6

4

5

5 7

7 22 23

1 2 3 4 5 6 7 23

1

2

3

4

5

6

6

22

Interquartile Range

Page 22: Inter quartile range

Purposes of the Interquartile Range (IQR)

The Interquartile Range (IQR) is a helpful measure of spread for two scenarios.

1. Rank ordered Data

2. Highly Skewed Data

1 2 3

3

5

4

4

5 6

4

5

5 7

7 22 23

1 2 3 4 5 6 7 23

1

2

3

4

5

6

6

22

Mean = 7Median = 5

Interquartile Range

Page 23: Inter quartile range

Purposes of the Interquartile Range (IQR)

The Interquartile Range (IQR) is a helpful measure of spread for two scenarios.

1. Rank ordered Data

2. Highly Skewed Data

1 2 3

3

5

4

4

5 6

4

5

5 7

7 22 23

1 2 3 4 5 6 7 23

1

2

3

4

5

6

6

22

IQR

Interquartile Range

Page 24: Inter quartile range

Purposes of the Interquartile Range (IQR)

The Interquartile Range (IQR) is a helpful measure of spread for two scenarios.

1. Rank ordered Data

2. Highly Skewed Data

1 2 3

3

5

4

4

5 6

4

5

5 7

7 22 23

1 2 3 4 5 6 7 23

1

2

3

4

5

6

6

22

IQR Standard Deviation = 5.3

Interquartile Range

Page 25: Inter quartile range

Purposes of the Interquartile Range (IQR)

The Interquartile Range (IQR) is a helpful measure of spread for two scenarios.

1. Rank ordered Data

2. Highly Skewed Data

1 2 3

3

5

4

4

5 6

4

5

5 7

7 8 9

1 2 3 4 5 6 7

1

2

3

4

5

6

6

IQR

8 9

Standard Deviation = 2.3

Notice how the Standard Deviation drops from

5.3 to 2.3.

Interquartile Range

Page 26: Inter quartile range

Purposes of the Interquartile Range (IQR)

The Interquartile Range (IQR) is a helpful measure of spread for two scenarios.

1. Rank ordered Data

2. Highly Skewed Data

1 2 3

3

5

4

4

5 6

4

5

5 7

7 8 9

1 2 3 4 5 6 7

1

2

3

4

5

6

6

IQR

8 9

Standard Deviation = 2.3

Notice how the Standard Deviation drops from

5.3 to 2.3. However the IQR stays

the same.

Interquartile Range

Page 27: Inter quartile range

The EndInterquartile Range